Preparation of aromatic mercury halides



Patented Aug. 25, 1953 PREPARATION OF AROMATIC MERCURY HALIDES Otto Dank and Jaroslav Nosek, Pardubice- Rybitvi, Czechoslovakia, assignors to Vychodoceske Chemicke Zavody, narodni podnik, Pardubice, Czechoslovakia i No Drawing. Application March 9, 1951, Serial $1.7 214,851. In Czechoslovakia February 19,

17 Claims. (Cl. 260-433) The present invention relates to the manufacture of aromatic mercury halides having the general formula: RHgY, wherein Rrepresents an aryl or a substituted aryl group, and Y represents a halide radical. 1

The present application is a continuation-inpart of our co-pending application filed October 1, 1947 having the Serial No. 777,364, now abandoned.

A prior art method for the manufacture of phenyl mercury chloride has been described by Nesmajanov in Berichte 62, 1015, wherein a solution of benzene diazonium chloride (diazotized aniline) is introduced with a solution of mercury chloride into dilute hydrochloric acid whereby a double salt is formed which is filtered with suction. This double salt is then introduced into acetone and decomposed by means of two equivalents of powdered copper (two gram-atoms copper to l gram-molecule of double compound), and the phenyl mercury chloride formed is extracted with acetone to separate it from the insoluble cuprous chloride also formed during the reaction. The yield obtained by Nesmajanovs process is 51% of the theoretical yield. The reaction proceeeds in accordance with the following equations wherein R represents an aryl group.

Such prior art methods of producing aromatic mercury halides obviously involve great expense in the use of costly organic solvents and large amounts of copper. Another disadvantage of the prior art methods is the necessity of separating the intermediate product, namely the double salt, from the reaction mixture prior to proceeding with the decomposition step which produces the aryl mercury halide.

Applicants have simplified this involved, time consuming and costly procedure by the use of a continuous and uninterrupted method of producing said aryl mercury halides. Another improvement of the instant invention over the prior art methods is the considerably increased yield obtained hereby. The sum total of the above mentioned and other advantages results in a superior commercial process particularly suit able for mass production of the aryl mercury halides which are useful in the elimination of fungi and molds and as seedimmunizing agents. Furthermore, the resultant products of this invention exhibit a particularly low solubility in water rendering them considerably more economical in use, said products maintaining their therapeutic activity over a longer period of time.

Accordingly, an object of the present invention,

is the development of a new process for the production of a high yield of aryl mercury halides.

Another object of this invention is the development of a superior commercial process of manufacturing aryl mercury halides.

A further object of this invention is the development of a continuous and uninterrupted method of producing aryl or substituted aryl mercury halides.

A further object of this invention is the development of a simplified process of producing aryl mercury halides.

Further objects and advantages of the present invention will be apparent from the following description.

It has now been discovered that aromatic mercury halides may be prepared in a continuous manner by diazotizing an aromatic amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 C., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt at a temperature of about 5-10 C. by adding one equivalent of metallic copper to the reaction mixture whereby the water insoluble aromatic mercury halide and Water-soluble cupric halide are formed in accordance with the following reaction:

where R represents an aromatic radical and Y represents a halide, and recovering a substantially pure aromatic mercury halide.

It has also been discovered that the decomposition reaction is an ionic reaction and can .thus be carried out in an aqueous medium or in only about 10% of the theoretical yield, whereas copper produces yields of up to about 86% of the theoretical yield. Accordingly, copper, copper bronze or molecular copper produced by the precipitation from cuprous salt solutions, in powdered form is utilized in the present inven-- tion. The decomposition reaction proceeds, in general, according to the following equation:

3. XRNzY.HgY2+Me mHgY+MeY2+N2, wherein X represents any or the following substituents: H, CH3, GaHtOI-I, OCH-I3, 0021-15, Cl,

OFFICE i Thus an essential feature of the instant inven-- tion resides in the utilization of only. one equivalent of metallic copper whose electro-positive po'-,

tential or divalency is completely utilized in the formation of water soluble: cupric chlorideor halide in the decomposition'reaction, as clearly illustrated by the above chemical reaction (Equation No. 3). This effects a saving of one halfof the amount of copper previously used as well as eliminates the prior art step ofseparatingthe insoluble cuprous chloride, CuzClz, from the insoluble aryl mercury chloride, RI-IgCl, by extraction with acetone, since water soluble cupric chloride, CuCl2, is formed in the instant process from which the insoluble aromatic mercury halide can be separated with facility.

Another important feature of the present process is the use of an aqueous medium for the decomposition reaction. This eliminates the use of' expensive solvents-heretofore utilized. Organic solvents miscible with water, such as acetone, methanol; ethanol and-the like, maybe added to the aqueous medium if a product of a higher degree of purity is desired. A mixture of water and organic water-miscible solvent may be advantageously used if a chemically pure'product is -desired. A small quantity of certain impurities which normally would be precipitated with the resultant product in an aqueous medium is eliminated from saidproduct in an aqueous organic medium'due'to the solubility of said impurities in amixture of water and organic solvent;

Another feature of the instant process is the use of'an acidicmedium for the decomposition reaction of the double diazonium salt. A neutral medium may also be utilized but it has been found that in an acidic medium, such as hydrochloric acid, the reaction proceeds in a more favorable manner.

A further essential feature of the present process is the maintenance of temperatures of about 5-10" C; during the decomposition reaction, such as by the addition of ice to the reaction mixture.

The initial diazotizing reaction also occurs at temperatures of about 0-5 C. by simultaneously cooling the reaction mixture during the formation of the diazonium compound (e. g. RNzCl). The diazonium compound is prepared by the known method-of diazotizing an aromatic amine with sodium nitriteor the like in the presence of'hydrochloric acid'or its equivalent.

A particular embodiment of this invention is the production of the-diazonium double salt with mercury halide by diazotizing aromatic amine in the presence of'mercury halide, the medium used herein being preferably an acidified aqueous medium. An aqueous medium containing water miscible organic solvents may also be utilized, if an unusually pure end product is desired. To thisreaction mixture which contains the double salt, metallic copperor similar copper product is added-, thereby producing the aromatic mercury halide inthe original acidified aqueous medium. Thus, it is apparent that a continuous method of producing an aromatic mercury halide has beenqdeveloped starting with an aromaticv amine, which does not require the separation of any intermediateproducts for the successful completion of the entire reaction. Consequently, both 4. the diazotizing reaction and the decomposition reaction can be carried out" in thesame medium which is anacidified aqueous solution to which may be added an organic water miscible solvent.

The. aryl-mercury bromide or iodide can be prepared by the same procedure as the chloride as represented by Equation No. 3. However, it is not, necessary to employ an exclusively bromid'eor iodide medium. The decomposition of the-double diazonium mercury chloride salt may be carried out in a chloride medium such as hydrochloric acid in' the presence of only one equivalent of a different soluble metallic halide such as the alkalimetal bromide or iodode. The bromide and iodide ions are more reactive than the chloride ion and consequently replace the chloride to form the correspondingaryl-mercury bromide or iodide, which results in a more insoluble halide ofan aromatic mercury compound. The reaction proceeds in accordance with the following formula, wherein Y'represents Br. or I, and Me represents Na or K:

Among the substantial advantages of themesent invention is the fact that the decomposition reaction is carried out in" an acidified aqueous insoluble mixture of-cuprous chloride and rphenyl.

mercury chloride, and necessitating the extraction of-the latter with acetone. It is a particular advantage of'the presentprocess that the entire course of reaction is carried out in a single phase without isolating any of the intermediate products. products, thearyl'mercury'halide, is isolated, after the total amount of copper used for the decomposition reaction has been'dissolved in the aqueous medium in the form of a soluble chloride or other cupric halide.-

This new process for the preparation of aryl mercury halides and similar compounds according to the present invention represent a considerable technical advance as compared with the methods heretofore known, and may be used as a preferred commercial process for mass production. The advantages of the process according to this invention as. compared with previous proc esses are simplification, a saving of half the amount of copper for the decomposition reaction of the double diazonium salt, while the expensive organic solvents for the extraction of the product may be entirely dispensed with, and the yield'is far higher.

' The following examples are additionally illustrative of the present invention and are notto be construedas limiting the scope thereof.

Emample I.

136 kgs. of mercuric. chloride are dissolved in 200- litres of hydrochloric acid having a specific gravity of 1.17, into which 46.5 kgs. of aniline are gradually introduced. The mixture is cooled by the addition of SOO'kgs. of ice, and diazotized with 35.0..kgs. of sodium nitrite, at a temperature not exceeding 5 C. The thick crystalline paste-like double compound obtained of benzene diazonium chlorideand mercuricchloride is de- Only the resultant crystalline point of CsHsHgCl is about 250 C. The mother liquid contains soluble cupric chloride, CuClz, which represents the total conversion of the metallic copper.

Example II 136 kgs. of mercuric chloride are dissolved in a mixture of 200 litresof hydrochloric acid having a sp. gr. of 1.17, and 600 litres of acetone, to which 71.5 kgs. of betanaphthylamine are gradually added. The mixture is cooled with 400 kgs. of broken ice and diazotized with 350 kgs. of sodium nitrite at a temperature not exceeding C. The produced thick crystalline paste of a double compound of beta-naphthalene diazonium chloride with mercury chloride is immediately decomposed in the mother liquor, without isolation therefrom by the admixture of 31.8 kgs. of copper, in powder form, at a temperature of 5-10 C. The produced insoluble raw beta mercury naphthyl chloride, CioHvHgCl, is removed by suction, washed with water and dried. The yield of the technically pure product amounts to 111 kgs. or 61.5% of the theoretical yield.

Example III 180 kgs. of mercury bromide are dissolved in 260 litres of hydrobromic acid having a density of 1.377, to which 53.5 kgs. of p-toluidine are gradually added. The mixture is cooled by the introduction of 350 kgs. of ice broken into pieces the size of a fist, and diazotized by means of 35.0 kgs. of sodium nitrite at a temperature not exceeding 5 C. The produced thick crystalline paste of the double compound of p-toluenediazonium-bromide with mercury bromide is decomposed, in this same medium, without isolation therefrom by means of 31.8 kgs. of copper bronze at a temperature of 5-10 C. by the subsequent addition of 150 kgs. of ice. The thusly formed insoluble raw mercury .p-tolyl-bromide, CHsCeHiflgBr, is removed from the mother liquor by suction, washed with water and dried. The yield of the technically pure product amounts to 132 kgs. which is 71.7% of theoretical yield. The melting point of CH3C6H4HgBr is 233 C. The total copper used in the decomposition reaction is converted into soluble cupric bromide, CuBrz, which remains dissolved in the mother liquor.

Example IV of 300 kgs. of ice and diazotized by means of 35.0

sodium nitrite at a temperature not exceeding 5 C. The produced crystalline paste of the double compoundof benzene-diazonium chloride with mercury chloride is decomposed in this same medium (in the same vessel) by the addition of 31.8 kgs. of copper in powder form at a temperature not exceeding 5 C., amount of ice is added if necessary to maintain the temperature at a maximum of 5 C. The proan additional duced insoluble raw phenyl mercury bromide,

also find a useful application in other types of method of manufacturing halide diflering from the types described above.

While we have illustrated and described the invention as embodied in methods of manufacturing aromatic mercury halides, we do not intend to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of our invention.

Without further analysis, the foregoing will so fully reveal the gist of our invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What we claim as new and desire to secure by Letters Patent is:

l. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aryl amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 C., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt at a temperature of about 5-10 C. by adding one equivalent of metallic copper to the reaction mixture whereby the water insoluble aryl mercury halide and water-soluble cupric halide. are formed in accordance with the following reaction:

wherein R represents an aryl radical and Y represents a halide, and recovering a substantially pure aryl mercury halide.

2. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing a substituted aryl amine, said substituent being selected from the group consisting of CH3, C2H5, OH, OCH:;, OCzHs, Cl, Br, I, F, N02 and COOH, in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 C., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt at a temperature of about 5-10 C. by adding one equivalent of metallic copper to the reaction mixture whereby the water insoluble substituted aryl mercury halide and water-soluble cupric halide are formed in accordance with the following reaction:

wherein R represents a substituted aryl radical and Y represents a halide, and recovering a substantially pure substituted aryl mercury halide.

3. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aromatic amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 C., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt C. by adding one equivalent of metallic copper to the reaction are. formed. in. accordance. with. the following.

wherein R represents an aromatic radical and Y- represents a-halide, and recovering a substantially pure aromatic mercury halide.

4. A commercial method-of manufacturing an aromatic mercury halide which comprises diazotizing an aromatic amine in the presence of a' mercury halide in an acidic aqueous medium containing awater miscible organic solvent at a temperature of about '5 0., whereby the diazonium double saltcontaining a mercury handle is formed, decomposing said double salt at a tem-- perature of about -10 C. by adding one equivalent of'metallic copper to the reaction mixture whereby the water insoluble aromatic mercury halide andwater-soluble cupric halide are formed in accordance with the following reaction:

wherein'R represents an aromatic radical and Y represents a halide, and recovering a substantially purearomatic mercury halide.

5. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aryl amine in the presence of a mercury wherein R represents an aryl radical and Y represents a halide, and recovering a substantially pure aryl mercury halide.

6. A commercial methodof manufacturing an aromatic mercury halide which comprises; diazotizing a substituted aryl amine, said-substituentbeing selected from the group-consisting of CH3,

Cal-I5, OH, OCI-Ia, OC2H5, Cl', Br, I, F, N02 and' COOH; in the presence of a mercury halidein an acidic aqueousmediumcontaining a water miscible organic solvent at a temperature of about O-5 0., whereby the diazonium" double salt containing amercury halide-is formed, decomposing said double salt at a temperature of about 5-l0 C. by adding one equivalent of metallic copper to the reaction mixture whereby the water insoluble substituted aryl mercury halide and water-soluble. cupric halide areformed-in ac cordance with the following reaction:

RN2Y;I-IgY2+Cu RHgY+CuY2 \-N2' wherein R represents a substituted aryl radical and Yarepresents ahalide, and recovering a sub-'- stantially pure substituted aryl mercury halide.

'7. .A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aromatic amine in the'presen-ce of a' mercury halide in an acidic aqueous medium at halide in thedouble salt, at a' temperature of about 510 C. by addingone equivalent of metallic copper to the reaction mixture whereby the water insoluble aromatic mercury halide and water-soluble cuprichalide are formed, and recovering. a substantially pure'aromatic mercury halide.

8. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aryl amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 C., whereby the diazonium double salt containing a mercury halide is formed, decomposingsaid double salt in the presence of one equivalent of a soluble halide salt, said halide being different from the halide in the double salt, at a temperature of about 5-10 C. by adding one equivalent of metallic copper to the reaction mixture wherebythe water insoluble aryl mercury halide and water-soluble oupric halide are formed, and recovering a substantially pure aryl mercury halide.

9. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing a substituted aryl amine, said substituent being selected from the group consisting of CH3, Cal-I5, OH, OCH3, OC2H5, Cl, Br, I, F, N02 and COOH, in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 0., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt in the presence of one equivalent ofa soluble halide salt, said halide being difierent from the halide in the double salt, at a temperature of about 510 C. by adding one equivalent of metallic copper to the reaction mixture whereby the water insoluble substituted aryl mzercury halide and water-soluble cupric halide are formed; and recovering a substantially pure substituted aryl mercury halide.

10. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aromatic amine in the presence of a mercury halid'ein an acidic aqueous medium containing a water miscible organic solvent at a temperature of about 0'-5 C., whereby the diazonium doublesalt containing a mercury halide is formed; decomposing saiddouble salt in the presence of one equivalent of a soluble halide salt; said halide being'different from the halide in the double salt, at a temperature of about 5-10" C. by adding one equivalent of metallic copper'to the reactionmixture whereby the water insolub'le'aromatic mercury halide and water-soluble cupric halide are formed, and recovering a substantially pure' aromatic mercury halide.

11. Acommercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aryl'amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0'.5 CL, whereby the diazonium double salt containing a mercury. halide is formed, decomposing said double salt at a. temperature of about 5-10? C. by adding one equivalent of powdered copper to the reaction mixture whereby the water insoluble aryl inercury halide and water-soluble oupric halide are formed in accordance with the following reaction:

' pure aryl mercury halide;

12. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing a substituted aryl amine, said subwherein R represents a substituted aryl radical and Y represents a halide, and recovering a substantially pure substituted aryl mercury halide.

13. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aromatic amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about -5 0., whereby the cliazonium double salt containing a mercury halide is formed, decomposing said double salt at a temperature of about 10 C. by adding one equivalent of powdered copper to the reaction mixture whereby the water insoluble aromatic mercury halide and water-soluble cupric halide are formed in accordance with the following reaction:

wherein R represents an aromatic radical and Y represents a halide, and recovering a substantially pure aromatic mercury halide.

14. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aryl amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5" C., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt at a temperature of about 510 C. by adding one equivalent or" metallic copper to the reaction mixture whereby the water insoluble aryl mercury halide and water-soluble cupric halide are formed in accordance with the following reaction:

wherein R represents an aryl radical and Y represents a halide, separating the insoluble aryl mercury halide from the aqueous medium and recoverying a substantially pure aryl mercury halide.

15. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing a substituted aryl amine, said substitutent being selected from the group consist ing of CH3, C2H5, OI-I, OCHs, OC2H5, Cl, Br, I, F, N02 and COOH, in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 C., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt at a temperature of about 5-l0 C. by adding one equivalent of metallic copper to the reaction mixture whereby the water insoluble substituted aryl mercury halide and water-soluble cupric halide are formed in accordance with the following reaction:

wherein It represents a substituted aryl radical and Y represents a, halide, separating the insoluble aryl mercury halide from the aqueous medium and recovering a substantially pure substituted aryl mercury halide.

16. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aromatic amine in the presence of a mercury halide in an acidic aqueous medium at a temperature of about 0-5 0., whereby the diazonium double salt containing a mercury halide is formed, decomposing said double salt at a temperature of about 510 C. by adding one equivalent of metallic copper to the reaction mixture whereby the water insoluble aromatic mercury halide and water-soluble cupric halide are formed in accordance with the following reaction:

wherein R represents an aromatic radical and Y represents a halide, separating the insoluble aromatic mercury halide from the aqueous medium and recovering a substantially pure aromatic mercury halide.

17. A commercial method of manufacturing an aromatic mercury halide which comprises diazotizing an aryl amine in the presence of mercury chloride in an acidic aqueous medium at a temperature of about 0-5 C., whereby the diazonium double salt containing mercury chloride is formed, decomposing said double salt in the presence of an equivalent amount of a soluble halide salt selected from the class consisting of NaBr, NaI, KBr, and KI, at a temperature of about 510 C., by adding one equivalent of metallic copper to the reaction mixture, whereby the water insoluble aryl mercury chloride and water-soluble cupric halide are formed, and recovering a substantially pure aryl mercury halide.

o'rro DANEK. JAROSLAV NOSEK.

References Cited in the file of this patent 

1. A COMMERCIAL METHOD OF MANUFACTURING AN AROMATIC MERCURY HALIDE WHICH COMPRISES DIAZOTIZING AN ARYL AMINE IN THE PRESENCE OF A MERCURY HALIDE IN AN ACIDIC AQUEOUS MEDIUM AT A TEMPERATURE OF ABOUT 0-5* C., WHEREBY THE DIAZONIUM DOUBLE SALTS CONTAINING A MERCURY HALIDE IS FORMED, DECOMPOSING SAID DOUBLE SALT AT A TEMPERATURE OF ABOUT 5-10 C. BY ADDING ONE EQUIVALENT OF METALLIC COPPER TO THE REACTION MIXTURE WHEREBY THE WATER INSOLUBLE ARYL MERCURY HALIDE AND WATER-SOLUBLE CUPRIC HALIDE ARE FORMED IN ACCORDANCE WITH THE FOLLOWING REACTION: 